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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>A Systematic Mapping Study on Software Ecosystems</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Olavo Barbosa</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Carina Alves</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Center of Informatics, Federal University of Pernambuco</institution>
          ,
          <addr-line>Cidade Universitária - 50740-560 - Recife/PE</addr-line>
          ,
          <country country="BR">Brazil</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>State Agency for Information Technology of Pernambuco</institution>
          ,
          <addr-line>Av. Rio Capibaribe, 147, São José - 50020-080 Recife/PE</addr-line>
          ,
          <country country="BR">Brazil</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2011</year>
      </pub-date>
      <fpage>15</fpage>
      <lpage>26</lpage>
      <abstract>
        <p>Software ecosystem is an approach that investigates the complex relationships among companies in the software industry. Companies work cooperatively and competitively in order to achieve their strategic objectives. They must engage in a new perspective considering both their own business and third party ones. Inspired from properties by natural and business ecosystems, a software ecosystem covers technical and business aspects of software development as well as partnership among companies. In this paper, we undertake a systematic mapping study to present a wide review of primary studies on software ecosystems. Systematic mapping is a methodology that gives, after a systematic research process, a visual summary map of its results. The search procedure identified 1026 studies, of which 44 were identified as relevant to answer our research questions. This study mapped what is currently known about software ecosystems perspective. We conclude that software ecosystems research is concentrated in 8 main areas in which the most relevant are open source software, ecosystem modeling, and business issues. The paper is intended to practitioners and academics investigating the field of software ecosystems. It contributes to summarize the body of knowledge in the field and direct efforts for future research in software ecosystems.</p>
      </abstract>
      <kwd-group>
        <kwd>software ecosystem</kwd>
        <kwd>digital ecosystem</kwd>
        <kwd>business ecosystem</kwd>
        <kwd>systematic mapping study</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1 Introduction</title>
      <p>
        Increasing attention is being paid to connectivity and dependency in relationships
between companies. Innovations no longer originate in a single organization; rather
they are co-innovations from different players [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Companies co-evolve capabilities
around a new innovation: they work cooperatively and competitively to support new
products, satisfy customer needs, and eventually incorporate the next round of
innovations [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. These loose networks of suppliers, distributors, outsourcing
companies, developers of related products or services, technology providers, and a
host of other organizations affect and are affected by, the creation and delivery of a
company’s own offerings [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. According to these viewpoints, researchers have coined
a new perspective to analyze the software industry, called software ecosystems. This
is an emergent field inspired on concepts from Moore and Iansiti’s [
        <xref ref-type="bibr" rid="ref2 ref3">2,3</xref>
        ] business and
biological ecosystem. This paper provides an overview of the current literature in
software ecosystem by conducting a systematic mapping study. Systematic mapping
is a methodology that is frequently used in medical research, but that has largely been
neglected in Software Engineering [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. The usual outcome is a visual map classifying
the results. It requires less effort than a systematic literature review while providing a
more coarse-grained overview. The remainder of this paper is organized as follows. In
section 2, we present the research method. We describe research questions,
inclusion/exclusion criteria, sources of studies, search strategy, data extraction and
synthesis of findings. In section 3, we present the results of this systematic mapping
study. In section 4 we outline our conclusions, limitations of this work and discuss
future research directions.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2 Research Method</title>
      <p>
        A review protocol specifies the methods that will be used to undertake a specific
systematic review and reduces the possibility of researcher bias [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. Although
systematic literature review and mapping study do not share all research procedures,
similar processes for searching are explicitly defined in the research protocol and
reported as part of the outcomes [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. A review protocol is an essential element to
conduct a secondary study that includes a description and rationale for the research
questions and the proposed methods. It also includes details of how different types of
studies will be located, appraised, and synthesized [
        <xref ref-type="bibr" rid="ref7 ref8">7,8</xref>
        ]. Thus, a protocol was
developed in order to define the main guidelines for conducting this study. According
to Brereton and others [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] a systematic map is used to describe the kinds of research
activity that have been undertaken and describes the studies rather than extracting
specific details. That is, it does provide a context for the later synthesis. According to
Kitchenham [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] a systematic map is a method that can be conducted to get an
overview of a particular research area. After this, the state of evidence in specific
topics can be investigated using a systematic review, if necessary. A research question
is a precisely stated question that guides the review [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. According to Budgen and
others [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], in systematic mapping study, the research question itself is likely to be
much broader than in systematic review. This is necessary in order to adequately
address the wider scope of study. Following these guidelines, we specified four
research questions (RQs) in order to characterize the field of software ecosystems:
(RQ1) What are the main characteristics of a Software Ecosystem? (RQ2) What is
currently known about the benefits, challenges and limitations of Software
Ecosystems? (RQ3) What are the implications of software ecosystem studies for
research and practice in Software Engineering? (RQ4) What are the main areas
studied from the perspective of Software Ecosystems? An important step in the search
for studies is to decide on criteria for including and excluding papers [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. Inclusion
and exclusion criteria are used to exclude studies that are not relevant to answer the
research questions. As pointed out by Petticrew and Roberts [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], inclusion and
exclusion criteria step is one of the activities of a mapping study very similar to a
systematic literature review. It comprises selecting the appropriate primary studies
from literature. The following list shows the inclusion criteria adopted: (1) Only
studies written in English; (2) Studies dealing and referencing any of the subjects
related to software ecosystems in their title or abstract; (3) Master and Doctorate
theses; (4) Studies unrestricted publication date; (5) “grey literature” [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] including
reports published independently by academic and industrial consulting organizations.
The exclusion criteria were: (1) Repeated studies found in different search engines. In
this case, just one study was considered; (2) Duplicate studies reporting similar
results. In this case, only the most complete study was considered; (3) Inaccessible
papers and books.
      </p>
      <p>
        Now, the search strategy and data sources are presented. According to Kitchenham
[
        <xref ref-type="bibr" rid="ref10">10</xref>
        ], researchers should specify their rationale for the use of electronic or manual
search or a combination of both. In this study, we used both electronic and manual
search procedures. In the manual search, we decided to find papers of a specific set of
conferences, researchers’ websites, and asking experts in the field of software
ecosystems. The justification for not using just electronic search procedures was
supported by recommendations from [
        <xref ref-type="bibr" rid="ref10 ref11">10,11</xref>
        ] who advocate the use of manual search
in order to obtain a broader list of potential papers to review. According to Petticrew
and Roberts [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] electronic databases are not the only source of literature, and
sometimes they are not even the most useful. Another reason was due to the fact that
software ecosystems is a novel field; therefore a manual search brings extra
confidence that more relevant papers might be found. The electronic search was
applied on the following Search Engines: IEEEXplore Digital Library, ACM Digital
Library, Elsevier ScienceDirect, EI Compendex, Scopus and Web of Science. These
digital libraries were selected because they are the most important repositories for
research in computer science. For the manual search, we considered 11 repositories,
where 9 were experts’ personal websites and 2 were the following conferences:
International Workshop on Software Ecosystems (IWSECO) and ACM Conference
on Management of Emergent Digital Ecosystems (MEDES). We used an approach to
derive terms from the research questions to create the search string. The strategy was:
(1) We derived the main search terms; (2) checked the keywords for relevant papers
already known and (3) looked for alternative forms of the terms such as synonyms
and relevant keywords. After that, we used Boolean operators OR and AND to
incorporate them into the search string. The first segment consisted of synonyms of
software ecosystem and the second one was derived from the main research questions
terms. Table 1 shows the final search string.
      </p>
    </sec>
    <sec id="sec-3">
      <title>3 Results</title>
      <p>In order to identify relevant studies, we used the following steps. First, we applied
the search string in the 6 search engines listed above. The digital databases provided
668 papers, but just 418 of them were available for download. After downloading,
only 117 papers were included according the inclusion and exclusion criteria. Since
we used several databases, many papers were duplicated. Finally, our list was reduced
to 56 papers. In the manual research, we found initially 358 papers. But just 271 were
available for download and only 127 papers were included. The sum of the both
manual and digital search was 183 papers. However, by crosschecking both manual
and digital databases we found some duplications and the final number decreased
from 183 to 141. After that, we reached the last stage when all papers were read and
44 relevant papers were selected for this systematic mapping study. Fig. 1
summarizes the selection process and presents the number of papers identified at each
step.</p>
      <p>
        Spreadsheets were created to record included and excluded papers for each stage. For
reading and extracting data, we used the Mendeley (http://www.mendeley.com/). We
created a form to record details about how each paper would answer the four research
questions. In the synthesis of findings, we adopted the method similar to the one used
by Dyba and others [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. We used a process based on the method of constant
comparison used in qualitative analysis. The process begins with coding the field
notes to extract pieces of text relevant to a particular theme or idea that is of interest
in the study. Finally, the results are examined for underlying themes and explanations
of phenomena [13]. In the Appendix, we present the complete list of selected studies
enumerated from S1 to S44. Fig. 2 illustrates the year wise distribution of selected
papers.
It is possible to notice an increase in the number of papers in the last two years. This
suggests a growing interest by the community in the field. Moreover, it indicates this
topic is relatively recent in publications. The oldest study found was published in
2003 (S43). We emphasize that papers like [
        <xref ref-type="bibr" rid="ref2 ref3">2, 3</xref>
        ] are not in the selected studies due to
the fact that they do not focus specifically on software ecosystem. Instead, these
papers primarily address the business ecosystem topic. Following, we discuss how
each research question was answered.
(RQ-1) What are the main characteristics of a Software Ecosystem?
Table 2 lists the main characteristics of software ecosystems identified in the
reviewed studies. A notable result is the relevance of open source models in the
context of software ecosystems. In fact, literature in open source software reinforces
the importance of collaboration among players to build a mature open source
platform. Other results state that software ecosystems are linked to natural
ecosystems, software product lines, and business ecosystems. These fields are
considered by many authors the origins of software ecosystem research.
Table 3 presents the most common terms and acronyms related to software
ecosystems. Given that software ecosystem is an emergent field, different research
and industry communities have been investigating the area independently. Therefore,
there is a lack of widely agreed terminology and characteristics of what constitutes a
software ecosystem.
      </p>
      <sec id="sec-3-1">
        <title>Mobile Learning Ecosystems / Mobile Ecosystem Free Open Source Software Ecosystem, Ecosystem Digital (Business) Ecosystem</title>
      </sec>
      <sec id="sec-3-2">
        <title>Open</title>
        <p>(RQ-2) What is currently known about the benefits, challenges and limitations of
Software Ecosystems?</p>
      </sec>
      <sec id="sec-3-3">
        <title>Benefits</title>
        <p>Fosters the success of software, the co-evolution and innovation inside the
organization, increase attractiveness for new players
Decreases costs involved in software development and distribution
Helps analyzing and understanding the software architecture in order to decide
which platform to use
Supports the cooperation and knowledge sharing among multiple and
independent entities.</p>
        <p>Enables analysis of requirements communication among stakeholders
Comes as alternative to overcome the challenges during design and
maintenance of distributed applications
Provides help to the tasks of business identification, product architecture
design, risk identification
Provides information for the product line manager regarding software
dependencies
Study ID
1,2,4,7
9,10,23</p>
        <p>3,10
11,23,24
20,33</p>
        <p>30
16,36
19
32</p>
      </sec>
      <sec id="sec-3-4">
        <title>Challenges and Limitations Study ID</title>
        <p>rEesptraebsleisnhtaintigonreolaftipoenosphliepasnbdettwheeiernknecoowslyesdtegmeinactthoerseacnodsypstreompomsinogdealninagd. equate 2, 15
Several key architectural challenges such as: platform interface stability,
evolution management, security, reliability, how to support the business 5,8,11,21,2
strategy, suitable architectures to support open source style development; how 7
open and flexible an architectural is.
Heterogeneity of software licenses and systems evolution in an ecosystem.
Organizations must manage these issues in order to decrease risks of 5,31,41
dependence.</p>
        <p>Companies have difficulty at establishing a set of resources in order to
differentiate from competitors. It is necessary a correct engagement of the 3,7
keystone organization in the social dimension.
cToemchmnuicnailcatioanndof resqouciiore-moregnatnsizinatgioenoaglraphbiacrrdiiesrtsribufteodr procjoeocrtds.ination and 16,30
Infrastructure and tools for fostering social interaction, decision-making and
development across organizations involved in both open source and proprietary 9,14,17,28
ecosystems.</p>
        <p>RQ-3) What are the implications of software ecosystem studies for research and
practice in Software Engineering?</p>
        <p>The findings indicate a strong significance of academic institutions involved in the
software ecosystem field with 70% (31 studies) of papers. The most active academic
institutions are: Utrecht University, in The Netherlands (S5, S11, S12, S15, S18, S19,
S29 and S41); University College London, in the UK (S5, S18, S19 and S29); Boston
University, in the USA (S20, S21, S22, S23, S24 and S26), Babson College, in the
USA (S20, S21, S23) and University of Lugano, in Switzerland (S4, S37 and S38).
We also mention London School of Economics in the UK (S36, S40) and Imperial
College London (S39). Although there are no many papers of these last two
institutions it appears that there is an emergent group of researchers studying this
topic. In addition, industrial institutions and government published 9 papers (S8, S10,
S12, S13, S24, S27, S28, S33 and S37) and 1 paper (S34), respectively. This result
suggests that the field is also investigated from the industrial standpoint.</p>
        <p>Regarding the research methods adopted by selected studies, we found a strong
importance of theoretical studies, with 12 papers (S5, S7, S8, S10, S16, S28, S33,
S34, S40, S42, S43 and S44). On the other hand, we found some studies that applied
qualitative methods, in special the case study method with 10 papers (S12, S13, S14,
S15, S18, S19, S21, S27, S29 and S41). This means that many researchers have been
conducting foundation studies that aim to define or classify the characteristics of
software ecosystems. Regarding the empirical papers, we observed that case studies
were conducted with varying level of rigor. The majority of studies were primary
studies; only 2 papers reported ad hoc literature reviews (S9 and S40). The topics
addressed by these studies, we identified that many studies point software evolution
(S31, S33, S34, S36, S37, S38, S39 and S43) and co-innovation (S3, S7, S43 and
S44) like an essential property of a product that sounds like a vital implication for the
industry development. We also identified that many studies have proposed approaches
for software ecosystem modeling, conceptual models or ecosystem analysis (S4, S5,
S12, S15, S20, S22, S40, S41, S43 and S44).
(RQ-4) What are the main areas studied from the perspective of Software
Ecosystems?
development. 10 papers present modeling techniques to represent or analyze software
ecosystems. Given that several authors come from the software engineering field, we
found 8 papers focusing on software evolution as part of a software ecosystem
strategy, 7 papers on software architecture and 4 papers relating software ecosystems
to software product lines. This demonstrates the relevance of traditional software
engineering areas to the current body of knowledge in software ecosystems. From the
managerial perspective, we found 7 papers dealing with business aspects of software
ecosystems and 4 papers on software co-innovation. Finally, 5 papers present results
on operating systems. These studies describe ecosystems such as Microsoft, SAP and
Linux. It is important to mention that some papers cover more than one aspect found
in the Fig. 3. Both S43 and S44, for instance, cover areas such as operating systems,
software architecture, open source, business and software evolution.</p>
        <sec id="sec-3-4-1">
          <title>Software Coinnovation (4)</title>
        </sec>
        <sec id="sec-3-4-2">
          <title>Software</title>
        </sec>
        <sec id="sec-3-4-3">
          <title>Evolution (8)</title>
        </sec>
        <sec id="sec-3-4-4">
          <title>Business (7)</title>
        </sec>
        <sec id="sec-3-4-5">
          <title>Operating</title>
          <p>Systems (5)
16
14
12
10
8
6
4
2
0</p>
        </sec>
        <sec id="sec-3-4-6">
          <title>Software</title>
        </sec>
        <sec id="sec-3-4-7">
          <title>Product Line (4)</title>
        </sec>
        <sec id="sec-3-4-8">
          <title>Software</title>
        </sec>
        <sec id="sec-3-4-9">
          <title>Architecture (7)</title>
        </sec>
        <sec id="sec-3-4-10">
          <title>Software</title>
        </sec>
        <sec id="sec-3-4-11">
          <title>Ecosystem</title>
        </sec>
        <sec id="sec-3-4-12">
          <title>Modeling (10)</title>
        </sec>
        <sec id="sec-3-4-13">
          <title>Open Source (15)</title>
        </sec>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4 Discussion</title>
      <p>
        This paper presented a mapping study on software ecosystems. A total of 44 papers
were included in the study. To the best of our knowledge, this is the first study aiming
to classify current research in software ecosystem. Secondary reviews like mapping
studies and systematic literature reviews are important methods to summarize and
provide overview of a maturing discipline [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. The main limitations of this mapping
study are eventual omission of papers and bias in the extraction data. Results indicate
that our choice of using manual search was crucial to increase the number of studies,
61% of papers were found through this strategy. To aid the selection of relevant
papers, we contacted experts to identify more papers. Even though this is considered a
useful strategy to conduct mapping studies, this approach may cause some bias.
Another potential risk that we may have missed relevant papers is due to the lack of
agreed terminology for software ecosystems and to the possible existence of relevant
papers that do not mention the keywords we chose. With respect to bias in the data
extraction, we had some difficulties to extract relevant information from the papers.
Several papers did not explicitly address the research questions in sufficient detail.
Our inclusion criteria clearly mentioned that selected papers should answer the
research questions. However, once we started reading the papers we noticed that
several issues were not clearly presented in the paper.
      </p>
      <p>
        It is important to note that our goal for this systematic mapping study was
providing an overview of current literature in software ecosystems; it was outside the
scope of the paper to evaluate the quality of studied papers or explain specific
findings. Further analysis is needed to address these specific issues. The mapping
study confirms that software ecosystem is an emergent field. The first study was
published in 2003 (S43), the last two years were the most productive period. The
outcomes of our study indicate that software ecosystem research has been mainly
inspired by studies from business and natural ecosystems [
        <xref ref-type="bibr" rid="ref2 ref3">2,3</xref>
        ] as well as traditional
software engineering research on software product lines, software evolution and open
source software. Currently, there are two key communities investigating the topic:
digital ecosystem from MEDES conference and IWSECO community. We observed
these two communities generally do not cite each other. Even though, both areas have
inherited similar concepts from business ecosystems. To strengthen the field, we
suggest more collaboration between both communities. Results reveal that key areas
investigated by the papers were open source software, ecosystems modeling and
business issues. Academic institutions published 70% of papers. This finding
reinforces the current trend in software engineering where academics publish the
majority of papers. A promising result that highlights the industrial relevance of
software ecosystems is that 10 papers presented case studies. However, the
methodology rigor and quality of these case studies were not carefully assessed. Our
preliminary opinion on this issue is that software ecosystems need more industrial
studies to increase the body of evidence in the field. Given the current state of
research and practice in software ecosystems, we envisage the need to conduct
integrative studies among research communities and industry.
      </p>
    </sec>
    <sec id="sec-5">
      <title>Acknowledgments</title>
      <p>We are grateful to authors in the field of software ecosystems for their contribution to
conduct this study.</p>
    </sec>
    <sec id="sec-6">
      <title>Appendix: The selected studies</title>
      <p>ID
S1
S2
S3
S4
S5
S6</p>
      <sec id="sec-6-1">
        <title>Reference</title>
        <p>Yu, L., Ramaswamy, S., Bush, J. Software Evolvability: An Ecosystem Point of View.
In: 3rd International IEEE Workshop on Software Evolvability. (2007)
Janner, T., Schroth, C., Schmid, B. Modelling Service Systems for Collaborative
Innovation in the Enterprise Software Industry. In: IEEE International Conference on
Services Computing vol. 2, (2008)
Arndt, J. M., Dibbern, J. Co-Innovation in a Service Oriented Strategic Network. In:
IEEE International Conference on Services Computing. (2006)
Lungu M., Malnati J., Lanza, M. Visualizing gnome with the small project
observatory. In: 6th Working Conference on Mining Software Repositories. (2009)
Jansen S., Brinkkemper S., Finkelstein, A. A Sense of community: A research agenda
for software ecosystems. In: Proceedings of the 31st International Conference on
Software Engineering. (2009)
Pettersson, O., Svensson, M., Gil, D., Andersson, J., Milrad, M., On the Role of
Software Process Modeling in Software Ecosystem Design. In: 2nd International
S7
S8
S9
S26
S27
S28
S29
S30
S31
S32
S33
S34
S35
S36
S37</p>
      </sec>
    </sec>
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